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Effects of different kinds of hormones on selenium accumulation in rice
Published in Gary Bañuelos, Zhi-Qing Lin, Dongli Liang, Xue-bin Yin, Selenium Research for Environment and Human Health: Perspectives, Technologies and Advancements, 2019
Z.H. Dai, Y. Yuan, H.L. Huang, M. Rizwan, S.X. Tu
We know that the hormones are widely used in the agricultural production. Auxins are arguably the most important signaling molecules in plants and have a profound impact on plant growth and development (Weijers & Wagner 2016). Gibberellic acid (GA3) is an important plant growth hormone which can accelerate stalk and leaf growth, improve seed shooting and increase fructification yield (Tang et al. 2000). The role of ethylene in defense responses to pathogens is widely recognized (Dubois et al. 2018). The 6-benzyl aminopurine (6BA) is one kind of cytokinin which can inhibiting the decomposition of chlorophyll, nucleic acid and protein in plant leaves, keeping green and preventing aging (Wojtania & Skrzypek 2014). Brassinosteroids (BRs) are steroidal plant hormones that are widely distributed in lower to higher plants, and the brassinolide (BL) exhibits the highest biological activity among naturally occurring BRs (Kim et al. 2000). Salicylic acid (SA) is a phenolic compound which can regulate plant physiological functions, such as seed germination, photosynthesis, respiration, growth and flowering (Rivas & Plasencia 2011). Plant growth regulator methyl jasmonate (MeJA) is a member of jasmonate group, which can regulates many aspects of plant growth and development. MeJA is known as a signaling molecule which plays a role in many biotic and abiotic stress responses.
Bacterial Synthesis of Metallic Nanoparticles
Published in Ramesh Raliya, Nanoscale Engineering in Agricultural Management, 2019
Shweta Agrawal, Mrinal Kuchlan, Jitendra Panwar, Mahaveer Sharma
Intuitively, nanoparticles can be used as biomarkers or as a rapid diagnostic tool for detection of bacterial, viral and fungal plant pathogens. Researchers have used nano-gold based immuno-sensors that could detect Karnal bunt (Tilletia indica) disease in wheat using surface plasmon resonance (SPR). Additionally, plants respond to different stress conditions through physiological changes such as induction of systemic defence, probably regulated by plant hormones: Jasmonic acid, methyl jasmonate and salicylic acid. This indirect stimulus was successfully harnessed in order to develop a sensitive electrochemical sensor, using modified gold electrode with copper nanoparticles, to monitor the levels of salicylic acid in the oil seeds to detect the fungi (Sclerotinia sclerotiorum). Researches on similar sensors and sensing techniques needs to be expanded for detecting pathogens, their by-products, or monitor physiological changes in plants and then apply pesticides and fertilizers as needed prior to the onset of symptoms (Khot et al. 2012). A mixture of titanium dioxide, aluminium and silica was reported to effectively control downy and powdery mildew of grapes, probably through direct action on the hyphae, interference with fungal mechanism of recognition of plant surface and stimulation of plant physiological defences. A new composition of nano-silver combined with silica molecules and water-soluble polymer proved effective in suppressing the growth of many plant pathogenic fungi and bacteria. Pythium ultimum, Magnaporthe grisea, Colletotrichum gloeosporioides, Botrytis cinere and Rhyzoctonia solani showed 100% inhibition of growth at 10 ppm concentration; whilst, Bacillus subtilis, Azotobacter chrococuum, Rhizobium tropici, Pseudomonas syringae, Xanthomonas compestris pv. and Vesicatoria showed 100% growth inhibition at 100 ppm concentration of the nanosized silica-silver (Sharon et al. 2010, Mishra and Singh 2014).
Alleviation of boron toxicity in plants: Mechanisms and approaches
Published in Critical Reviews in Environmental Science and Technology, 2021
Tianwei Hua, Rui Zhang, Hongwen Sun, Chunguang Liu
Besides nutrient elements, some exogenous chemicals (some can be naturally produced by the plant) were also found to alleviate B toxicity in plants via triggering ROS scavenging mechanisms (Table 2). For example, some plant growth regulators (PGRs) (e.g. salicylic acid, nitric oxide, methyl jasmonate) have been reported to mediate antioxidative systems of plants under B stress. Salicylic acid (SA), a hormone-like substance playing an important role in plant growth regulation, has been found to regulate antioxidant enzymes in carrot, spinach, barley, and wheat exposed to excess B (Eraslan et al., 2007; Eraslan et al., 2008; El-Feky et al., 2014; El-Shazoly et al., 2019). In recent years, nitric oxide (NO), an important signaling molecule in plants, has been observed to help plant tolerate excess B via regulating antioxidant enzymes (Aftab et al., 2012; Esim & Atıcı, 2013; Kaya & Ashraf, 2015; Farag et al., 2017; Dilek Tepe & Aydemir, 2017; Kaya et al., 2019). Jasmonic acid (JA) and its methyl ester, methyl jasmonate (MeJA), are important plant hormones and signal molecules. Both the two hormones have been reported to be able to improve plant tolerance to high levels of B by regulating antioxidant enzyme activities (Aftab et al., 2011; Sarabandi et al., 2019; Zhao et al., 2019).
Roles of phytohormones in mitigating abiotic stress in plants induced by metal(loid)s As, Cd, Cr, Hg, and Pb
Published in Critical Reviews in Environmental Science and Technology, 2023
Zhi-Hua Dai, Dong-Xing Guan, Jochen Bundschuh, Lena Q. Ma
However, the effects of methyl jasmonate on photosynthesis are dose-dependent. Methyl jasmonate is a plant signal-regulating morphogenesis, which responds to abiotic stress. For example, application of 1.1–2.2 mM methyl jasmonate enhances photosynthesis in trifoliate orange. In contrast, application of 4.4 mM methyl jasmonate to trifoliate orange decreases its photosynthesis (Kurowska et al., 2020). This is because higher jasmonate inhibits stomatal development in plants (Han et al., 2018), thereby reducing plant photosynthesis. However, our knowledge on the mechanisms of hormone-mediated regulation of photosynthesis is still fragmentary.